Natural Antimicrobials

Question 1

Animal-derived antimicrobials

Answer 1

Lysozyme
Lactoperoxidase system
Lactoferrin, lactoferricin

Question 2

Plant-derived anitmicrobials

Answer 2

Herb and spice extracts

Question 3

Microbial products

Answer 3

Bacteriocins ex: Nisin

Question 4

Lactoperoxidase system

Answer 4

• Natural enzyme found in mammalian milk and body fluids such as tears or saliva
• acts as a catalyst oxidising thiocyanate ions in the presence of hydrogen peroxide into hypthiocyanous acid.
• The acid dissociates in milk and the hypothiocyanate ions react with sulphydryl groups to inactivate the metabolic enzymes in milk

Question 4

Lysozyme

Answer 4

• hydrolytic enzymes characterized by their ability to cleave the bonds in
  peptidoglycan - compromises the integrity of the cell wall, causing the lysis of bacteria.
• Naturally present in substantial amounts in mammalian milk and avian eggs.
• GRAS
• preserve food and beverages, mainly by adding it to the final
  product and also used as a protective matrix

Question 5

Lactoferrin

Answer 5

• component of the whey protein of milk of most mammals,
  probably except dogs and rats
• The antimicrobial activity of lactoferrin is due to its ability to bind to iron and make it
  unavailable to bacteria
• major component of the immune system; antibacterial activity is an
  important component of the innate immunity of the body.
• Human body cells can produce lactoferrin and it is also found in many organs e.g.
  kidneys, lungs, gallbladder, pancreas, intestine, liver
• Mainly used in Pharmaceuticals and cosmetics

Question 6

Herbs and spices: Thymol

Answer 6

is the main monoterpene phenol found in the essential oils extracted from plants
belonging to the Lamiaceae family - flavouring and preservative agent - antimicrobial and
antioxidant properties - meats, salads, and soups - maintain the safety of foods and reduce
their salt content with the final aim to decrease the incidence of hypertension.
Other components occurring in essential oils (i.e. carvacrol, carvone, cinnamaldehyde, citral,
p-cymene, limonene, and menthol)

Question 7

Herbs and spices: Eugenol

Answer 7

significantly inhibitory effects on numerous kinds of food source
microorganisms, and the mechanisms are associated with reducing the migratory
and adhesion and inhibiting the synthesis of biofilm and various virulence factors of
these microorganisms.

Question 8

Herbs and spices: Thymol

Answer 8

Main monoterpene phenol found in essential oils in the Lamiaceae family.
Reduces salt content with the aim to decrease the incidence of hypertension